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Wyświetlanie 1-7 z 7
Tytuł:
Diversity of tissues in acanthodians with Nostolepis-type histological structure
Autorzy:
Valiukevicius, J
Burrow, C.J.
Powiązania:
https://bibliotekanauki.pl/articles/22517.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
histology
acanthodian
dentine
Devonian
Acanthodii
Silurian
bone
Nostolepis
tissue
paleontology
mesodentine
Opis:
Acanthodian scales with Nostolepis−type histological structure are separated into five groups based on the presence/absence and extent of stranggewebe, odontocytic and syncitial mesodentine networks, cellular unipolar mesodentine, bone−like mesodentine and durodentine in scale crowns. Two new families of acanthodians are erected, based primarily on histological structure of scales: the Vesperaliidae (stranggewebe extending throughout the scale crown) and the Acritolepidae (bone−like mesodentine in the scale crown). The latter family includes species erected for articulated fish. The families Tchunacanthidae and Lenacanthidae are united in the single family Tchunacanthidae, characterized by having scale crowns with mesodentine formed mainly by unipolar cells. A sixth group, which we exclude from the Nostolepis−type, has scale crowns composed of dentine without lacunae, plus durodentine, and bases with only rare osteocyte cavities. The new groups promote the revision and reassignment of many “nostolepid” taxa, in particular removing many species from the genus Nostolepis. Four new genera are erected: Pechoralepis (including part of Nostolepis), assigned to Acritolepidae nov.; and three genera assigned to an indeterminate family, which scales are composed of only odontocytic mesodentine without stranggewebe: Nostovicina (including part of Nostolepis), Nobilesquama (including part of Nostolepis), and Peregrinosquama (including part of Watsonacanthus). Histological structures are considered the primary characters of taxonomical value when based on isolated scales. Unfortunately, scale histology is unknown for most articulated acanthodians.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Early Devonian ischnacanthiform acanthodian Ischnacanthus gracilis (Egerton, 1861) from the Midland Valley of Scotland
Autorzy:
Burrow, C. J.
Newman, M.
den Blaauwen, J.
Jones, R.
Davidson, R.
Powiązania:
https://bibliotekanauki.pl/articles/139010.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Acanthodii
Ischnacanthus
Lochkovian
palaeohistology
dentition
fałdopłetwe
akantody
lochkov
dewon wczesny
paleohistologia
uzębienie
Opis:
Ischnacanthus gracilis (Egerton, 1861), the only ischnacanthiform acanthodian from the Lochkovian Lower Old Red Sandstone of Scotland, is known from hundreds of specimens in institutional collections worldwide. Despite this relative abundance, morphology and histology of its skeletal elements have rarely been investigated. Surface details of spines, dental elements, and scales are often not visible in specimens because they are usually split through the middle. We have examined a broad size range of fish, from 35 mm to 250 mm long. Several intact (not split) specimens have been collected in recent years and acid-prepared to show fine details of the dermal and dental elements. We have also used scanning electron microscopy of scales, jaws and dental elements, denticles and fin spines, and serial thin sectioning of articulated specimens, to document their structure. Some of our notable observations include: identification of ventral lateral lines, double-layered subtessellate calcified cartilage forming the jaws, and the probable occurrence of extraoral tricuspid denticles on the jaws of most fish. Examination of the size range, body proportions and dentition of institutional specimens gives no support for recognising more than one species in the Midland Valley localities.
Źródło:
Acta Geologica Polonica; 2018, 68, 3; 335-362
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acanthodian jaw bones from Lower Devonian marine deposits of Podolia, Ukraine
Autorzy:
Voichyshyn, V.
Szaniawski, H.
Powiązania:
https://bibliotekanauki.pl/articles/22218.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
acanthodian jaw
jaw bone
Lower Devonian
Devonian
marine deposit
Podolia
Ukraine
Acanthodii
Ischnacanthiformes
Opis:
Ischnacanthiform acanthodian dentigerous jaw bones from the Lower Devonian (Late Lochkovian) of Podolia are described for the first time. One new genus and one new species are established. Podoliacanthus gen. nov. is diagnosed as having small−sized jaw bones, the presence of specific accessory cusps/denticles on the medial side of teeth of the lateral tooth row, and groups of denticles forming the lingual tooth row. Podoliacanthus zychisp. nov. is distinguished in having elongated slender jaw bones and lateral teeth with one medial side denticle. Besides, three species are described in open nomenclature: Podoliacanthus sp. 1, while similar to Podoliacanthus zychi sp. nov., differs in having stronger posterior inclination of the teeth tips and presence of well developed flanges of the teeth, P. sp. 2 has quite robust jaw bones and teeth with two medial side denticles, and Podoliacanthus sp. 3 has small narrow jaw bones and teeth with three medial side denticles. Morphology of the lingual tooth row is considered to be a diagnostic feature of generic and higher taxonomic levels, while accessory medial cusps/denticles of the teeth are regarded as diagnostic features at species level. The new genus also occurs in Upper Silurian or Lower Devonian deposits of North Greenland. Preservation of the jaw bones possibly depends on their secondary mineralization.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acanthodians from the Lower Devonian (Emsian) ‘Placoderm Sandstone’, Holy Cross Mountains, Poland
Autorzy:
Burrow, C. J.
Szrek, P.
Powiązania:
https://bibliotekanauki.pl/articles/139217.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Acanthodii
Machaeracanthus
Striacanthus
Onchus
Emsian
Lower Devonian
Polska
fałdopłetwe
akantody
ems
dewon dolny
Polska
Opis:
The Lower Devonian ‘Placoderm Sandstone’ in the Holy Cross Mountains (HCM) is filled with abundant impressions of disarticulated vertebrate remains. The only acanthodian macroremains named to date are fin spines of Machaeracanthus polonicus Gürich. Fin spine impressions in slabs from the Winna Formation (Emsian) at Podłazie Hill (near Daleszyce) in the southern HCM, and also the Barcza Formation (?Lochkovian) at Barcza Quarry, Miedziana Góra Conglomerate (?Lochkovian), Gruchawka, and Zagórze Formation (middle–upper Emsian) at Bukowa Mountain in the northern HCM, reposited in the University of Warsaw, Polish Geological Institute-National Research Institute, Warsaw, and Natural History Museum, London collections, have been cast and studied in order to better document this poorly known taxon. As noted in other Machaeracanthus species, we have found that M. polonicus has two different morphotypes of spines, which abut lengthwise to form a pair of spines. Our investigations show that the fin spine assemblage includes Onchus overathensis as well as M. polonicus, and probably another undetermined acanthodian. The affinities of O. overathensis are reassessed. It is here considered to be a diplacanthiform, and reassigned to the genus Striacanthus, as S. overathensis. Acanthodian scapulocoracoids have also been identified, as well as tightly spiralled toothwhorls which could be from an acanthodian.
Źródło:
Acta Geologica Polonica; 2018, 68, 3; 307-320
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acanthodian fish trace fossils from the Early Devonian of Spitsbergen
Autorzy:
Wisshak, M
Volohonsky, E.
Blomeier, D.
Powiązania:
https://bibliotekanauki.pl/articles/21739.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fish trail
trace fossil
Old Red Sandstone
fossil
Devonian
Acanthodii
Undichna
Spitsbergen
paleontology
Svalbard
Opis:
We describe and interpret Undichna septemsulcata isp. nov., from the fluvial Old Red Sandstone deposits of the Early Devonian Wood Bay Formation, of Northern Spitsbergen (Svalbard). Its delicate scratch pattern, comprising one unpaired median groove and three pairs of lateral grooves, all with a regular in−phase sinusoidal wave pattern of equal wavelength, allow the reconstruction of the number, position and relative spacing of the fins. The comparatively high−amplitude median groove is attributed to the main propelling action of the tail or caudal fin, the inner pair of the lateral grooves to the action of the pelvic fins, and the low−amplitude outer set of duplicate grooves to bifurcated pectoral fins, respectively. The in−phase geometric pattern is explained by a distance between the unpaired fin (caudal or anal fin) to the pectoral fins corresponding to one wavelength and a position of the pelvic fins half way in between. The direction of movement and the mode of locomotion of the trace maker (a carangiform to ostraciiform type) are deduced. This analysis is leading to an acanthodian (possibly Diplacanthus) as the most probable trace maker. By being Pragian or early Emsian (Early Devonian) in age, according to vertebrate and palynomorph biostratigraphy, these specimens are among the world’s oldest trace fossils made by a vertebrate.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Frasnian acanthodians from Central Iran
Autorzy:
Hairapetian, V.
Valiukevicius, J.
Burrow, C.J.
Powiązania:
https://bibliotekanauki.pl/articles/20209.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Acanthodii
Central Iran
Climatiidae
dental element
Diplacanthidae
Early Frasnian
Frasnian
Iran
Ischnacanthiformes
acanthodian
paleontology
histology
Devonian
systematics
Opis:
Two vertebrate−bearing horizons in the basal Frasnian carbonate of the Chahriseh section, northeast of Esfahan, yielded microremains of thelodonts, placoderms, acanthodians, actinopterygians, chondrichthyans, and sarcopterygians, considerably expanding the vertebrate faunal list for the strata. Acanthodians comprise a diverse association of climatiids, diplacanthids, and ischnacanthiforms, including the previously recorded climatiid Nostolepis sp. cf. N. gaujensis, as well as one new climatiid genus and several taxa left in open nomenclature. Climatiid Iranolepis ginteri gen. et sp. nov. is diagnosed by having scales with a highly raised medial crown area separated by steep slopes from lateral crown areas; an odontocytic mesodentine of maximum extent in the crown, distinguished by extensive network of fine canaliculi with abundant tiny osteocytes; and a poorly developed stranggewebe system. Other scales with fan−like symmetrically grooved crowns conform to the Diplacanthus−type histologically, and have many characters in common with Milesacanthus antarctica from the Aztec Siltstone of Antarctica. Osseous gnathal elements include mesodentinous tooth whorls from an ischnacanthiform or climatiid, and ischnacanthiform jaw bones with large chambers for vascular canals, distinctly separated cylindrical tooth cusps along the lingual ridge, and wide−based, triangular, weakly striated cusps on the main lateral ridge. The acanthodian association, accompanied by the Frasnian conodonts of the middle Mesotaxis falsiovalis to Palmatolepis hassi zones and zonal thelodonts Turinia hutkensis and Australolepis seddoni, is proving useful for biostratigraphy, showing similarities with assemblages from both Gondwana and the Old Red Sandstone Continent.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Wenlock-Pridoli [Silurian] acanthodian fishes from Lithuania
Autorzy:
Valiukevicius, J
Powiązania:
https://bibliotekanauki.pl/articles/21880.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
histology
fish
Ischnacanthiformes
acanthodian
Vesperalia perplexa
Silurian
Acanthodii
Arenaceacanthus arcuatacanalis
Bracteatacanthus assiduus
morphology
Fecundosquama basiglobosa
Rohonilepis breviornatus
acanthodian fish
new species
Climatiiformes
Lithuania
paleontology
Opis:
Five new monotypic acanthodian genera and five new species are described from the Silurian (Wenlock to Pridoli) of Lithuania. Two new genera and species, Vesperalia perplexa and Fecundosquama basiglobosa, belong to climatiiform and three, Arenaceacanthus arcuatacanalis, Bracteatacanthus assiduus, and Rohonilepis breviornatus, to ischnacanthiform acanthodians. Vesperalia perplexa has high−crowned scales with ridges that cross the entire surface or frequently fade mid−crown and after a smooth area continue on the posterior edge. Stranggewebe in the crowns of V. perplexa scales has large oriented lacunae and a well−developed system of main vascular canals. Fecundosquama basiglobosa scales have an undeveloped neck, a crown with only marginal sculptural incisions and have an unusually large deep base. Simple bone−like mesodentine in the crowns of F. basiglobosa scales lacks principal vascular canals. Arenaceacanthus arcuatacanalis has diagnostic scales with anterior ridges that fade out at one−third of crown length, and crowns composed of simple acellular mesoand durodentine with the original arcuate radial vascular canals over the base. Bracteatacanthus assiduus scale crowns have short ridges of asymmetric profile and an antero−median sulcus, whereas scales of Rohonilepis breviornatus have sharp symmetric subradial crown ridges sloping towards the base. Scale crowns of B. assiduus and R. breviornatus are composed of dentine and durodentine, but the former is distinguished by a second area of multibranched radial vascular canals positioned high in the neck.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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